Moffat left the social media platform in 2012, and will not be returning to it any time soon.

Speaking at Comic-Con international in San Diego about Sherlock, he said: "I think Twitter is a useful tool for promoting a show, but I think it is the worst possible form of audience research, it really is."

"That is not a typical audience member talking. It might be interesting, it might be witty, it might be clever, it might be insightful, but it's now what they're all saying."

He said one of the biggest pitfalls was "mistaking Twitter's reaction for the audience's reaction".

"They are not the same thing," he said. "They're not even supposed to be the same thing.

"People on Twitter are having fun, they're making gags... it's like overhearing a pub conversation, when you're at a pub do you tell the truth, or do you try and get attention?"

Moffat, actor Rupert Graves, who plays Lestrade, and the show's executive producer, Sue Vertue, also revealed some details about the planned 90-minute Sherlock special which will air later this year.

Moffat said: "The Sherlock special is set in Victorian times, so it's a different version of the show we're used to. It's like we checked the books and discovered we'd set it in the wrong time period by mistake and it's like we're correcting it for 90 minutes."

"We're really proud of it, we think it's a real cracker. But that'll be it until series four.

The fourth instalment of the show is due to return in 2017, and Moffat revealed they have not started writing it yet.